Why does the national media believe they understand America?

I'm not one to get into debates about liberal vs. conservative media, but I do think that the national media is completely out of touch with the lives of most Americans. What's funny to me is that most media people live very narrow and sheltered lives. Lots of very prominent news people rarely leave their New York neighborhoods. Moreover, they consider the vast majority of the nation to be "flyover country," a condescending term that implies an insignificance to what happens anywhere except New York or LA. What's ironic about this is that the news media so often seems shocked when the people in those "flyover states" behave in a way that they didn't forsee. It's like it's hard for them to fathom that not everyone is an Ivy-League liberal who lives on the upper east side of New York.